Sony finally made "waves" this year. I think the kicker is apparently they have a 500/2.8 in the pipeline, but I think that's wishful thinking on some people's thoughts. They do have a fast long telephoto under construction, their press room has tons of images of their products including the prototypes they have shown somewhere.
But they really aren't a new brand - they're just finally updating the Minolta line. And they're not making a bazillion copies of almost the exact same lens a la Canon did with their entry level models. i.e.: 35-70, 35-80, 28-70, 28-80, 28-105, 35-105, 35-135, 28-135 etc. Sigma and Tamron have a lot of lenses for the alpha mount, and plus all the old Minolta lenses.
The rumbling mostly is that their lenses cost more than C/N. But Canon has a problem in that their 200/2 IS costs 1k more than Nikon. Normally it's the other way around.